Set sous vide to 130°F for medium-rare and let it heat-up as you prep your steaks.

Trim elk steaks of any silverskin.

Sprinkle a little salt and pepper over the elk steaks and add to your sous vide bag. Make sure to not overlap the steaks - if you have to use multiple bags to ensure none of the steaks overlap, do it.

Add a rosemary sprig and sliced garlic clove to the bag. The amount you use depends on how much you would use with cooking normal steaks. If I’m putting 2 pounds of elk steak in the bag, I’ll slice one medium clove of garlic and add half a sprig of rosemary.

If you’re using a vacuum seal bag, vacuum seal the bag, and put it in the sous vide heated pot for 1 hour (add 30 minutes to the time if you’re cooking from frozen). If you’re using a ziploc bag and doing the water displacement method (where you slowly lower the bag into the water to get the air out of the bag before completely sealing it), so ahead an slowly start to lower the bag in the water, seal it up, and let it cook in the sous vide pot for 1 hour (again, adding 30 minutes to the time if you’re cooking from frozen).

After the 1 hour of cooking, you’ll pull the elk steaks out of the sous vide pot, and will notice that they’re still reddish-pink. That’s fine, you’re going to get the color in the next step.

Get a cast iron skillet smoking hot - often times, I achieve this by sticking the pan in a 350°F oven for 10 minutes. The point is to get the pan as hot as you possible can so you get a really good sear on the elk steaks. The next step is going to be fast, so make sure you have your elk steaks near by, ready to go, as well as, a couple pats of butter and a cutting board they can rest on after they’re seared.

Add a little olive oil to the pan to help prevent the elk steaks from sticking. Add the elk steaks, leftover rosemary sprig, garlic, and a pat of butter to the top of each elk steak. Cook the elk steaks on one side for 2 minutes, flip, and cook on the other side for 1 minute.

Remove the seared elk steaks to cutting board and tent with foil for 5 minutes.

Mise en place! French for "putting in place;" in other words, prep work. Mince the garlic, set aside. Get a bowl or cup out that will hold about 2 cups of ingredients. Put the balsamic vinegar, blueberries, rosemary, honey, brown sugar, and cognac in the container to make it easier to add to the hot pan later.

Melt the butter in a saucepan.

Add the minced garlic and saute until you start to smell that nutty, garlic smell (about 2 minutes).

Pour in your balsamic vinegar blueberries mix.

Zest the lemon into the pot. Slice the lemon open, and squeeze 1 lemon half of juice into the pan. If you don’t have a lemon juicer, juice the lemon over a bowl to prevent the seeds from going in the pan.

Low simmer sauce for 30 minutes to reduce down and make balsamic reduction. Stir often. If you want to speed this up, just turn the heat up to medium and cook at a hotter temperature, but remember to check on the sauce more often to make sure it doesn’t get overcooked and continuously stir.

When the blueberries get soft, use a spoon to squish the berries against the saucepan. If you have an immersion blender, use that to help speed things up, but remember to keep it in the sauce or balsamic blueberries sauce will go everywhere (I'm speaking from experience and a newly, stained Under Armour shirt).

The sauce is done when it’s thick enough to stick to the back of a spoon. Serve over steaks or alongside steaks as a dipping sauce.